Embodiments of the invention relate generally to a fast addressable multi-resolution lens system, and more particularly to a camera system that includes low and high resolution modes.
Optical recognition camera systems may be used to recognize objects in an image in industrial and security settings, as examples. In an industrial setting, these systems may be used in industrial inspection, serving the role to not only do basic inspections (component present/absent) but also to direct a mechanism to reject parts, position robots, or update databases, as examples.
In a security application, as another example, cameras may be used to identify individual faces in a crowd. In such an application, a system may use a first camera viewing a wide scene that may include a crowd of multiple people as well as other objects in a scene and a second camera having a higher resolution as well as a face recognition application that may be used to identify an individual within the crowd. Methods of two-dimensional (2D) face recognition have been widely published and are in use commercially today. These methods include such tools as large scale correlation, key point selection, wavelets and segmenting of the face into key components. In one example, a “self portrait” mode is made specifically to snap a picture when a face is positioned in the center of the camera view.
Today, dual resolution systems, or optical systems are often based upon dual camera systems or mechanical zooms. In these systems, the large view camera examines the scene, and then a high resolution camera is panned and tilted to a specific location. Thus, for high magnification in a traditional system, some means for pan and tilt are needed to move the small field-of-view for focusing on various specified locations. Typical security camera pan tilt units are large units that move the whole camera and are motorized by stepper motors or potentiometer equipped DC motors.
These systems that include movement of the whole camera have the disadvantage, especially in a security application, of potentially indicating to imaged subjects that they are in fact being viewed. For example, movement of a whole camera may draw the attention of the subject being imaged, and any panning and tilting of such a camera to coincide with the movement of the subject may indicate that the subject is of particular interest. Typical systems may also have the disadvantage of the cost of a second camera, and a speed of the pan/tilt mechanism may be too slow to follow subject movement. Further, these systems can have a reduced reliability because of the number of components and because of the mechanical mechanisms used to pan/tilt or autofocus the camera, which can lead to additional maintenance costs and system downtime. Thus, for reasons of reliability, cost, and performance, it is desirable to minimize the number of moving elements in a face recognition system.
One solution for a multiple resolution camera may be to integrate precise actuators into the lens itself. Small simple actuators can provide the limited pan, tilt, and focus without moving the entire system. However, this technology, based on piezo-driven lead screws, is typically only capable of short travel and light loads, thus limited to smaller lenses. Overall, these systems having piezoelectric focus mechanisms also tend to be expensive.
Therefore, it would be desirable to design an optical system and a method of fabricating same that overcomes the aforementioned drawbacks.